Shareholders' Equity (Company's Common Share Repurchase And Issuance Activity) (Details) - $ / shares	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019
Increase (Decrease) in Treasury Stock
Treasury stock, beginning balance, Shares	22,305,464	21,083,972
Stock Repurchased During Period, Shares	1,723,081	1,429,154
Shares of treasury stock reissued for equity incentive plans	(209,315)	(207,662)
Treasury stock, ending balance, Shares	23,819,230	22,305,464
Treasury stock, beginning balance, Weighted-average price per share	$ 46.53	$ 44.59
Treasury Stock Acquired, Average Cost Per Share	98.77	74.89
Treasury stock, ending balance, Weighted-average price per share	$ 50.30	$ 46.53